Visual FoxPro

Remove All S/MIME Security Layers (UnwrapSecurity)

Demonstrates the Chilkat Mime.UnwrapSecurity method, which removes supported S/MIME security layers and restores the underlying MIME content. It takes no arguments and handles both layer orders: signed-then-encrypted and encrypted-then-signed.

Note: The file paths are relative to the application's current working directory. Absolute paths may also be used. Supply the paths appropriate to your own environment.

Background: A message can be both signed and encrypted, in either order, producing nested S/MIME wrappers. UnwrapSecurity peels them all off in one call — verifying signatures and decrypting as it goes — so you do not have to detect the layering and call Verify and Decrypt in the right sequence yourself. Decryption still requires the recipient's certificate and private key to be configured.

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Visual FoxPro

LOCAL lnSuccess
LOCAL loMime

lnSuccess = 0

*  Demonstrates the Mime.UnwrapSecurity method, which removes supported S/MIME security layers and
*  restores the underlying MIME content.  It takes no arguments and handles both layer orders
*  (signed-then-encrypted and encrypted-then-signed).

loMime = CreateObject('Chilkat.Mime')
lnSuccess = loMime.LoadMimeFile("qa_data/secured.eml")
IF (lnSuccess = 0) THEN
    ? loMime.LastErrorText
    RELEASE loMime
    CANCEL
ENDIF

*  A single call peels off the signature and/or encryption layers.  (Decryption requires the
*  appropriate certificate/private key to be configured first.)
lnSuccess = loMime.UnwrapSecurity()
IF (lnSuccess = 0) THEN
    ? loMime.LastErrorText
    RELEASE loMime
    CANCEL
ENDIF

? "Security layers removed. Content-Type is now: " + loMime.ContentType

RELEASE loMime